May be you did not strech the film between right roll and left roll. You need to play with winding knob to strech the film before exposing. It must be tight but dont rip the film also.
My Leica had it , I went a famous repairman 400 kilometers far and he hold the body and pressed the plate with two fingers and everything sat where it might be sit before.
Press the plate with two first fingers and check from the side , does it parallel to film and cover.

Good luck ,